1. Field of the Invention
This invention relates to a circuit breaker including a bimetal trip triggering mechanism and more particularly, it pertains to a circuit breaker having a U-shaped bimetal which is adapted for self contained adjustment without reliance on adjacent parts for calibration.
2. Description of the Prior Art
Most conventional electrical circuit breakers do not include bimetals which change the direction of current flow 180.degree.. The 180.degree. directional change gives rise to magnetic forces tending to separate the conducting members so associated. Exemplary of a breaker incorporating a bimetal which changes the current path approximately 180.degree. in U.S. Pat. No. 3,341,791, issued Sept. 12, 1967 to J. H. Leonard and assigned to the same assignee as the instant invention.
In more common useage are straight bimetals which further extend the current in its existing direction and those that change the direction by approxmately 90.degree.. These types of bimetals avoid the aforementioned magnetic forces. However, they also dictate different locations for cooperating parts which preclude use of the space efficient design shown in the aforementioned Leonard reference.
Furthermore, most circuit breakers rely on adjacent parts for the purpose of adjustment of the bimetal member. Adjustment of the typical thermostat element is generally accomplished after the thermostat element and associated parts have been securely mounted within the circuit breaker case. Often these elements are completely enclosed by housing parts which are fixedly secured together. Accordingly, initial and subsequent calibrations of the bimetal must be made in a restrictive environment.